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What is Rust?

Michael Pollick
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Updated: May 21, 2024
Views: 318,791
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Rust is another name for iron oxide, which occurs when iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time. Over time, the oxygen combines with the metal at an atomic level, forming a new compound called an oxide and weakening the bonds of the metal itself. Although some people refer to rust generally as "oxidation," that term is much more general; although rust forms when iron undergoes oxidation, not all oxidation forms rust. Only iron or alloys that contain iron can rust, but other metals can corrode in similar ways.

The main catalyst for the rusting process is water. Iron or steel structures might appear to be solid, but water molecules can penetrate the microscopic pits and cracks in any exposed metal. The hydrogen atoms present in water molecules can combine with other elements to form acids, which will eventually cause more metal to be exposed.

If sodium is present, as is the case with saltwater, the corrosion is likely to occur more quickly. Meanwhile, the oxygen atoms combine with metallic atoms to form the destructive oxide compound. As the atoms combine, they weaken the metal, making the structure brittle and crumbly.

Some pieces of iron or steel are thick enough to maintain their integrity even if iron oxide forms on the surface. The thinner the metal, the better the chance that rusting will occur. Placing a steel wool pad in water and exposing it to air will cause rusting to begin almost immediately because the steel filaments are so thin. Eventually, the individual iron bonds will be destroyed, and the entire pad will disintegrate.

Rust formation cannot be stopped easily, but metals can be treated to resist the most damaging effects. Some are protected by water-resistant paints, preventative coatings or other chemical barriers, such as oil. It also is possible for one to reduce the chances of rust forming by using a dehumidifier or desiccant to help remove moisture from the air, but this usually is effective only in relatively small areas.

Steel is often galvanized to prevent iron oxide from forming; this process usually involves a very thin layer of zinc being applied to the surface. Another process, called plating, can be used to add a layer of zinc, tin or chrome to the metal. Cathodic protection involves using an electrical charge to suppress or prevent the chemical reaction that causes rust from occurring.

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All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Michael Pollick
By Michael Pollick
As a frequent contributor to All The Science, Michael Pollick uses his passion for research and writing to cover a wide range of topics. His curiosity drives him to study subjects in-depth, resulting in informative and engaging articles. Prior to becoming a professional writer, Michael honed his skills as an English tutor, poet, voice-over artist, and DJ.
Discussion Comments
By anon993251 — On Nov 02, 2015

Does it affect water pipe lines?

By anon991883 — On Jul 25, 2015

Rust occurs when iron water and oxygen mix together. It's normally called oxidation. Rust is a chemical reaction.

By anon971278 — On Sep 24, 2014

I know what rust is but why does it form? Can metals that are not alloys of iron rust?

By anon944368 — On Apr 07, 2014

I find it so interesting that people usually fight rust wherever it appears, but many others find the texture so appealing. I see rust textures in advertisements, games and movies regularly.

By anon930344 — On Feb 04, 2014

What are human impacts on rust?

By anon350499 — On Oct 05, 2013

How do you measure rust?

By anon296083 — On Oct 09, 2012

What is the best way to measure rust?

By anon259824 — On Apr 08, 2012

Do you have to have oxygen for something to rust?

By anon255577 — On Mar 18, 2012

There seem to be a lot of questions on how to prevent rust, but how would you speed up rusting without salt water, and what's all this about vinegar?

By anon255431 — On Mar 17, 2012

How is rust so damaging?

By anon251404 — On Feb 29, 2012

Why does rust have that red color though?

By anon249165 — On Feb 20, 2012

What happens when you take a mixture of bleach, salt and water, put aluminum in it and cover it with a thin layer of vegetable oil? Will it corrode, and if so, will it corrode faster in mild temperatures, cool or under a lamp that is 40 watts?

By anon233361 — On Dec 06, 2011

I recently did a science fair project on rusting. I am in year 9. I used water spray, salt water, tap water and white vinegar (mixed with water). I used three iron strips in each. They were all submerged completely except for the spray of course. In the end vinegar rusted the most. It formed a lot of rust and it lost the most weight too. Tap water was next then salt water.

From the research I've done, vinegar removes rust, and salt water is supposed to rust a lot. I am supposed to explain why what happened happened. I can't find anything, though. Can anyone help me? It's urgent.

By anon231703 — On Nov 26, 2011

I'm sorry, but I can't find the author of this page! I need it for my bibliography! please help!

By anon223040 — On Oct 17, 2011

what will be the effect if a baby puts a rusty object on his mouth?

By anon220396 — On Oct 07, 2011

How would I cite this?

By anon218651 — On Sep 29, 2011

Thank you guys so much! This helped so much with my science fair project! Thanks. This was very useful.

By anon216901 — On Sep 23, 2011

Does the density of a liquid affect the speed of rusting a metal?

By anon216700 — On Sep 22, 2011

I'm doing a project on the speed of rust in different liquids such as coke. Can anyone provide any help?

By anon209469 — On Aug 26, 2011

Only iron oxide is rust. Other metals undergo oxidation to form oxides, but the resulting material is an iron oxide, not rust.

By anon204906 — On Aug 10, 2011

Does the presence of rust on a surface make that surface more prone to oxidation? Let's say, if a metal box was left to the elements and produced some rust, if you took said box, cleaned it and kept it isolated from the elements (a.k.a. outside), would that box be more prone to oxidation in the future?

By anon191530 — On Jun 29, 2011

So many questions on here with no or bad answers.

Will soda (coke) oxidize (rust) metal? Yes. All sodas contain phosphoric acid. This is where the bubbles come from, this also decreases the pH of the soda and speeds up the rusting process. P.S. To the doctor who said co2 does not cause oxidation you are wrong co2 is corrosive.

What gives rust its orange-red color? The element Fe (iron) is what turns rust red.

Does the presence of sodium speed up the rusting process? Yes. Sodium increases the conductivity of water, making it a better electron transfer medium and speeding up the oxidation process.

Any health effects upon exposure to deep well water containing rust due to corrosion in the pipeline?

Depends on many factors, generally speaking, however, no. However, rust on piping makes an excellent site for harmful organisms to form colonies, and severely rusted pipes tend to have poor seals, allowing a whole host of things to seep into your water. If you have high iron in your water it is generally a good idea to find a way to reduce it either though treatment (which well water often needs anyway) or replacing damaged pipes.

How can rust be prevented with just a simple substance? There are whole fields of science dedicated to this question. Generally speaking, coating iron in any compound that seals off the iron surface from oxygen: e.g., paint, plastic, oil.

What are the positives and negatives of rusting? Well, the negatives part is easy. If the metal rusts away, it can fail, potentially causing great damage or bodily injury. The positive is a bit harder to answer. The short version is rusting is bad. However, not all rust is the same. For example, the Statue of Liberty was originally the color of a freshly minted penny. Over time as the surface copper oxidized, it formed a hard protective layer protecting the rest of the metal surface from exposure to oxygen, and greatly slowing down the "rusting" of one of the world most iconic national treasures.

How does the chemical change take place (from metal+water+oxygen = rust)? I couldn't think of a way to explain this easily but the information is available online.

Why does the metal rust more when the plating is scratched? Often metal is treated to resist rusting, but this treatment is only "skin deep." You create a galvanic cell, dramatically increasing the flow of electrons in a very small area.

Do you think iron would rust slowly, quickly, or at all in distilled water? Very slowly, or depending on what exactly your "iron" is made from, not at all.

“I am doing an experiment trying to find out in what type of water iron would rust the fastest...” The slowest will be distilled water by far. The tap water and salt water could be a toss up depending on where you get your tap water from, and how much salt you put in it. Also make sure you use the distilled water to make your salt water otherwise you will have salty tap water and it will spike your results.

As for removing them from the water, I would say no. However, drawing some of the water off, and pouring it back into your sample jar several times a couple times a day could increase the dissolved oxygen content of your water samples and will increase the rate of oxidation.

How long do you think an experiment like this would take? Depends how much rust are you looking for, the quality of your iron and the properties of your sample water types. Most often, nails are galvanized or treated in some way to resist rusting and may takes weeks or longer to show any real signs of rusting.

Why does water rust less than coca cola, or apple juice? And why does the iron in the apple juice turn black? Coca-Cola and apple juice have a lower pH than water. Low pH solutions will rust iron faster, and the reason it turns black in apple juice is much like a blue and yellow marker make green; the compounds in apple juice, when mixed with iron, form a material black in color.

I have an indoor water fountain with metal cups are now rusting...” To remove the rust, drain the fountain let it dry, Go buy CLR and a stiff brush rinse and scrub. As for preventing the rust from coming back, the short answer is there's nothing you can do.

By anon164034 — On Mar 30, 2011

if i put an iron nail in hydrochloric acid and another in sea water (salty water) which would rust more?

By anon160568 — On Mar 16, 2011

I am doing a science experiment. What will rust faster in just plain tap water - an iron nail or a small piece of steel wool? I am guessing steel wool because of the surface area. Can anyone verify this for me? Thanks so much!

By anon160237 — On Mar 15, 2011

If a piece if rust is say, 1mm (0.039'') thick, what thickness of steel has been lost? I have heard a wide variance of answers, so is there a definitive one please?

By anon158198 — On Mar 06, 2011

someone asked how does rust harm you. here's the answer: it doesn't. it harms metal.

By anon138273 — On Dec 30, 2010

Thanks for the info!

By anon135819 — On Dec 20, 2010

How does rust harm you?

By anon134425 — On Dec 14, 2010

thanks this really helped because I am doing a science fair project on how to make a nail rustproof. all of this information was very helpful!

By anon132924 — On Dec 08, 2010

This really helped me with my science project I'm working on. now we needed five references and I have picked up the most and interesting facts on this website. hopefully my teacher will think my project is decent.

By anon130726 — On Nov 29, 2010

can liquids form rust?

By anon126128 — On Nov 11, 2010

what chemical and physical changes happen to metal when it rusts?

By anon124402 — On Nov 05, 2010

I have a indoor water fountain with metal cups which is where the water flows over. The metal cups are now rusting and I would like to know how to remove the rust and refinish the cups so they won't rust anymore.

By anon121882 — On Oct 25, 2010

This really helped me! I am so thankful I've been looking for a long time for information about rust.

By anon117425 — On Oct 10, 2010

I'm doing a science fair project on "which liquid rusts nails the fastest, water, vinegar, coke, or orange juice. I don't know what to start researching. What do I do?

By anon116299 — On Oct 06, 2010

Why do nails rust with exposure to salt water and not to vinegar?

By anon114784 — On Sep 29, 2010

Rust is formed by oxidation and oxygen mixing together on the surface of metal or iron cause it to become bumpy and brown-red like.

By anon107768 — On Aug 31, 2010

Is rust bad for your health?

By anon107766 — On Aug 31, 2010

How can we make rust on metal without water?

By anon100706 — On Jul 31, 2010

how do you remove rust?

By Chanwoot — On Jul 14, 2010

I have a problem concerning rust on aluminum?

Anybody know of a cause, please help me.

By anon88638 — On Jun 06, 2010

can fizzy drinks make something rust and why?

By anon88636 — On Jun 06, 2010

why does rust gives a reddish color?

By anon86948 — On May 27, 2010

here we know about rust. it's very easy to learn.

By anon86700 — On May 26, 2010

what procedure should I use to make iron rust with which liquids?

By anon86615 — On May 26, 2010

Apparently coca cola can help remove rust. does anyone know if tap water causes rust more than coke?

By anon85407 — On May 20, 2010

i don't understand. Can any substance make something rust?

By anon83503 — On May 11, 2010

it rusts faster when the plating is scratched off

because it opens the pits and pockets and lets the water and air flow through it quicker.

By anon83502 — On May 11, 2010

i highly disagree that rust grows faster in salt water. it grows quicker in regular water.

By anon81740 — On May 03, 2010

rust grows quicker in salt water. a good experiment would be: air, water, salt water.

By anon81192 — On Apr 30, 2010

rust is bad.

By anon80339 — On Apr 27, 2010

OK I am doing a science experiment and does vinegar, tap water, or Sprite make a fishing hook rust the fastest?

By anon76458 — On Apr 10, 2010

how can i separate the mixture of rust and magnetite layer?

By anon72891 — On Mar 24, 2010

I just did an experiment and I found out that vinegar will rust things the most in four weeks.

By anon70554 — On Mar 15, 2010

i need help badly. what helps rust grow the fastest? lemon juice, water or vinegar? please respond. Quickly!

By anon69903 — On Mar 10, 2010

thanks heaps. that's really good.

By anon69526 — On Mar 08, 2010

I am also doing a science experiment. Which metal )steel, aluminum, copper) will rust the fastest in water, lemon juice, and ammonia?

By anon69381 — On Mar 08, 2010

Are there any environmental effects of rust?

By anon69260 — On Mar 07, 2010

one way to get something to rust is to fill up a cup with water. Then put a nail in the cup filled with water. Once you do that put in salt. After that sit back and watch the nail rust away.

If it doesn't I recommend using a different kind of salt.

By anon68651 — On Mar 03, 2010

How do different liquids affect the amount of rust on metal?

By anon68224 — On Mar 01, 2010

I'm doing the following experiment: I put

in four cups different materials like: a penny, a bolt, a paper clip, an aluminum. Then I put a little bit of water in each cup. In each cup I put different drinks like: water, water with salt, coke, orange juice, vinegar. In those materials I put five pennies, a bolt, paper clip and aluminum. How can I do this project? What is the problem, hypothesis,procedure, data, what's happening and conclusion. If I have a question, can I write you again?

By anon66123 — On Feb 17, 2010

I'm also doing a science fair project (which is a huge pain in the but by the way!), but this site has helped me a lot. You see, my project is on what dissolves the rust on a rusty nail the most: bleach, water, baking soda, salt or sea salt.

By anon64531 — On Feb 08, 2010

I'm doing a science fair on which dark soda will remove rust from a rusted nail the fastest and i want to know how long it takes so i can see how long i can keep an eye on it.

thank you so much! this site helped me a whole bunch! -Kayla

By anon62978 — On Jan 29, 2010

Why does water rust less than coca cola, or apple juice? And why does the iron in the apple juice turn black?

By jmortiz22 — On Jan 23, 2010

Which liquid will rust a nail the fastest, tap water, lemon juice or coke?

By anon61554 — On Jan 20, 2010

This has really helped me with my science fair project.

By anon61208 — On Jan 18, 2010

I'm doing a science project on what makes a nail rust faster: tap water or salt water? could you tell me how long it usually takes a nail to rust so i can figure out when i need to get it done?

By anon60363 — On Jan 13, 2010

i have six test tubes. One contains tap water, the other distilled water, the other distilled water with salt, the other distilled water with oil, the other dry sand and the final one wet sand and all off them had one nail inside. i would want to know the effects.

By anon59111 — On Jan 06, 2010

I would like to know if you using a rusty hair clip in your hair would affect your scalp, and your hair growth.

By anon58632 — On Jan 03, 2010

This website really helped me with my project.

By anon54430 — On Nov 30, 2009

Some metals that can rust are steel, copper and bronze. But anything with iron in it will rust.

By anon53900 — On Nov 25, 2009

i am doing a science fair project and i would like to know what metals can rust.

By anon53434 — On Nov 21, 2009

can a nail rust in fresh water?

By anon52061 — On Nov 11, 2009

I need to know what gets rid of rust faster?

vinegar or baking soda? please let me know. Thank you. (:

By anon51955 — On Nov 10, 2009

i read this thing where you put 4 tsps. of bleach and 2 tsps. of vinegar into a jar with whatever you want to rust, fill it up with water just past the metal. it'll rust in about 5 minutes.

By anon51684 — On Nov 08, 2009

can rust form on any steel?

By anon50996 — On Nov 02, 2009

I can't find ten good facts about rust. can you help me? i am doing a science fair project. please help.

By anon50994 — On Nov 02, 2009

Can rust be immediate or does it take a few days?

By anon50561 — On Oct 29, 2009

How does rust get in iron or steel?

By anon49852 — On Oct 23, 2009

why don't you give the author because people are using this as bibliogrophy and you have to have the author for that! Duh!

By anon49684 — On Oct 22, 2009

Thank you for the information. This is just what i needed. Thank you.

By anon49364 — On Oct 20, 2009

rust is browny orange.

By anon48917 — On Oct 15, 2009

Oh gee, thank you so incredibly much. I am doing a science project, and this information will definitely help me ace it! Go science!

By anon48458 — On Oct 12, 2009

hey thanks so much. doing a science project and this will totally get me to the county fair. Thanks so much!

By anon44149 — On Sep 05, 2009

The term "rust" refers only to oxides of iron - therefore it is not correct to refer to oxides of other metals (such as aluminum and copper) as rust.

In addition oxidation is the processes by which rust, and other oxides, are formed - therefore the first sentence is also incorrect. It would be more accurate to equate "rusting" and "oxidation", however only when referring to iron.

By anon40159 — On Aug 06, 2009

Please can you tell me the outcome of the following reactions with their equations:

1) Iron left to rust for a few days in Aqueous HCl.

2) Iron left to rust for a few days in Aqueous NaCl.

3)Iron left to rust for a few days in Aqueous

HNO3(Nitric Acid).

4) Iron left to rust for a few days in Aqueous

NaNO3(Sodium Nitrate).

By anon38108 — On Jul 23, 2009

How long it would it take enough rust to build up inside a 100 lb. oxygen tank to cause it erupt when full?

By anon29842 — On Apr 09, 2009

i'm going to do a project called 'which metals will be effected by salty water?' can you tell me what grade project this is, because i want to do like a 6th or 7th grade project although i'm in 5th grade? can you please explain this to me in some easier words?

By john11 — On Mar 11, 2009

I am about to do an experiment involving the rusting of nails.

Can you tell me of an unusual way to rust nails?

I will be using 4 test tubes.

One will have a galvanized nail and the rest will be regular iron nails.

Thanking you,

John

By winnie1180 — On Mar 03, 2009

i'm doing a project about oxidation of *rocks* and i have no idea what it is! please help. it would be really nice 'cause I found oxidation pictures but no info... thanks!

By anon26847 — On Feb 19, 2009

I am doing a project on what how does coating an iron nail with nail polish affect the rate that it will rust in vinegar? - Briana 4th grade

By anon26256 — On Feb 10, 2009

i'm doing a science project. so how could you prevent metal from rusting without paying the price?

By anon24770 — On Jan 18, 2009

Is rust another metal on top of the metal when the water hits it?

By anon24500 — On Jan 13, 2009

is rust harmful to the skin?

By anon23102 — On Dec 16, 2008

does salt water rust metal?

By anon22172 — On Nov 29, 2008

which kind of liquid rusts iron the fastest? -Michael, 7th grade

By anon20635 — On Nov 04, 2008

why do we get tetanus? is there anyway to prevent from this disease?

By anon19799 — On Oct 19, 2008

1 Do you think iron would rust slowly, quickly, or at all in distilled water?

2 I am doing an experiment trying to find out in what type of water iron would rust the fastest; we are doing so with iron nails and salt water, tap water, and distilled water... should I leave the iron nails in the water the whole time, or occasionally remove them from the water?

3 How long do you think an experiment like this would take?

By anon19782 — On Oct 19, 2008

Wait, so are there any other substances (other than steel or iron) that can have rust grow on it?

And does the original way of using baking soda and vinegar actually take off 100% of the rust on any substance?

By anon19430 — On Oct 12, 2008

wait so the scientific name is oxidation?

By anon18933 — On Oct 02, 2008

I am doing a report and this will definitely help me get a good grade!!!

By anon17264 — On Aug 26, 2008

what are the 2 types of rust?

By anon13840 — On Jun 05, 2008

What is the most efficient way to treat rust. Please reply. I have an assignment on this.

By anon13470 — On May 28, 2008

why is it that only metals experience corrosion? what is it about their structure that makes them experience corrosion?

By anon11342 — On Apr 14, 2008

Well robbi i think it is because there is more area for the water and oxygen to get to create more rust. Nick Rodriguez 8th grade

By robbi — On Apr 02, 2008

1. How does chemical change take place(from metal+water+oxygen = rust)?

2. Why does the metal rust more when the plating is scratched?

By anon10120 — On Mar 20, 2008

i heard that heat and sand get rid of rust or just keep scrub it the rust with warm water and then i think that should do it.

By anon10074 — On Mar 19, 2008

What gets rid of the rust?

By anon9113 — On Feb 28, 2008

what are the positives & negatives of rusting ?

By anon9049 — On Feb 27, 2008

I know the answer to some of these Q's:

1. No, It's not bad for you.

2. I don't think so, but I'm not sure.

3. No, the gas in it is CO2, (Carbon Dioxide) the fizziness does nothing unless the Coke is mixed with O2. (Oxygen)

4. Copper, iron and steel rust orange/red because that is how the oxygen mixes with the metal.

5. Paint and oil are great substances for prevention of rust.

6. It depends how much O2 is in the air that you put the rusting metal in.

Yours Faithfully,

Dr Ryuta Kawashima

P.S. Is Mascara good for the bugs on your eyelashes?

By anon6971 — On Jan 14, 2008

how long does the rusting process take?

By anon6930 — On Jan 13, 2008

how can rust be prevented w/ just a simple substance?

By anon6741 — On Jan 08, 2008

What gives rust its orange-red color?

By anon5837 — On Dec 07, 2007

can coke make something rust?

By anon5587 — On Nov 30, 2007

Does the presence of sodium speed up the rusting process?

By anon486 — On Apr 26, 2007

Any health effects upon exposure to deep well water containing rust due to corrosion in the pipeline?

Michael Pollick
Michael Pollick
As a frequent contributor to All The Science, Michael Pollick uses his passion for research and writing to cover a wide...
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